1. Field
Embodiments of the present disclosure relate to a solenoid valve for a brake system, and more particularly, to a solenoid valve for a brake system, capable of reducing noise and vibration during valve operation.
2. Description of the Related Art
A hydraulic brake system for braking is necessarily mounted in a vehicle. Recently, a variety of systems for obtaining a stronger and more stable braking force have been provided. As examples of a hydraulic brake system, there are an anti-lock brake system (ABS) configured to prevent sliding of wheels during braking, a brake traction control system (BTCS) configured to prevent slippage of driving wheels during sudden unintended acceleration or sudden acceleration, an electronic stability control system (ESC) configured to stably maintain a driving condition of a vehicle by controlling a hydraulic brake fluid by combining the ABS and BTCS, and the like.
In order to implement a brake system, a plurality of electronically controlled solenoid valves are installed in a modulator block and a flow path (hydraulic circuit) formed in the modulator block is selectively opened or closed by the solenoid valves. Solenoid valves are divided into normally open (NO) type solenoid valves which usually remain in an open state and normally closed (NC) type solenoid valves which usually remain in a closed state.
An NC type solenoid valve includes an orifice therein to allow a fluid (oil) to selectively move, and an armature installed to be movable upward and downward seals the orifice. The armature is accommodated in a cylindrical sleeve and selectively opens or closes the orifice due to an electromagnetic force of a magnet core provided above the sleeve to control a flow of the fluid.
Meanwhile, the armature which moves upward and downward while the solenoid valve operates may make a noise while a top side thereof collides with the magnet core and a bottom side thereof collides with the orifice. Since such operation noise may be introduced into a vehicle during braking and may be recognized by a driver, it is necessary to minimize the operation noise.